Method and an arrangement for filtering milk

ABSTRACT

The present invention provides an arrangement for filtering milk in a milking system, wherein said arrangement comprises a movable filter magazine provided with at least three filter devices ( 8 ), each of which comprises a tube housing a disposable filter and a support structure for supporting the disposable filter, and each of which is connectable to said milking system for filtering milk therein; and an actuating device for connecting each of said at least three filter devices, one at a time, to said milking system.

FIELD OF INVENTION

[0001] The present invention relates generally to dairy farming andparticularly to an arrangement and a method, respectively, for filteringmilk in a milking system.

BACKGROUND

[0002] There are many duties to carry out on a dairy farm and some ofthese have to be carried out on specific times. For instance, when milkhas been collected from a milk storage tank by a milk lorry, e.g. everysecond day, the milk storage tank has to be cleaned. Suitably, the restof the milking system is then cleaned along with the milk storage tank.

[0003] Due to hygienic requirements the milking system comprises a milkfilter, which milk filter further has to be cleaned or replaced by a newmilk filter regularly, generally, three times per day and night.Suitably, the milk filter is renewed or replaced when the milking systemhas been cleaned. As the milk filter is renewed or replaced regularly,some of the renewals or replacements will need to be carried out at oddworking hours, e.g. during the night.

[0004] It is therefore desirable to perform the renewal or replacementof the filter at least partially automatically such that the operator ofthe milking system need not attend the milking system during these oddworking hours.

[0005] In EP 0653153 A1 a milking machine is disclosed provided with oneor more filtration devices, each being provided with a filter, forfiltering milk. When the milking machine is cleaning a cleaning liquidis led through a filter in a direction opposite to that in which themilk passes during filtration. A disadvantage of such a filtrationdevice is that the back flush cleaning involves risks of catching dirtin the filter, which thereafter may come loose during milking andcontaminate the milk.

[0006] Further, EP 0653153 A1 describes that several filter devices,connected by a piping, may be used, wherein one filter device may berenewed while another one is used for filtering milk. A disadvantage ofsuch an arrangement is that the piping connecting the filtersnecessarily include corners, branches and recesses, may be difficult toclean. Further, such filter devices have to be renewable, and thusdisposable filters are not suitable to be used.

SUMMARY OF THE INVENTION

[0007] An object of the present invention is to provide an arrangementand a method, respectively, for filtering milk in a milking system,which allow an operator of the milking system to change disposablefilters in a milking system only once per day and night, suitably at atime convenient to the operator.

[0008] This object, among others, is according to the present inventionattained by arrangements and methods, respectively, as defined in theappended claims.

[0009] Further features and advantages of the present invention will beevident from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention will become more fully understood from thedetailed description of preferred embodiments given below and theaccompanying FIGS. 1-6, which are given by way of illustration only, andthus, are not limitative of the present invention, wherein:

[0011]FIG. 1 shows schematically a milking system including a filterarrangement according to the present invention;

[0012]FIG. 2 illustrates a filter arrangement including a revolverfilter magazine according to a first embodiment of the presentinvention;

[0013]FIG. 3 illustrates a cut along the line II-II of FIG. 2;

[0014]FIG. 4 shows a support structure for a filter sock of a filterdevice suitable to be used with the present invention;

[0015]FIG. 5 illustrates a filter arrangement including a linear filtermagazine according to a second embodiment of the present invention; and

[0016]FIG. 6 illustrates a cut along the line VI-VI of FIG. 5.

DETAILED DESCRIPTION OF EMBODIMENTS

[0017] In the following description, for purpose of explanation and notlimitation, specific details are set forth, such as particulartechniques and applications in order to provide a thorough understandingof the present invention. However, it will be apparent for a personskilled in the art that the present invention may be practiced in otherembodiments that depart from these specific details.

[0018] A first embodiment of the present invention will now be describedwith reference to FIGS. 1-4.

[0019] An automatic milking system, as shown in FIG. 1, comprises amilking robot 1; a milk storage tank 3; a milk line 2 connecting themilking robot 1 with the milk storage tank 3; a filter arrangement 4 forfiltering milk in said milking system; and a controller 5 forcontrolling the milking system, e.g. controlling cleaning of the milkingsystem.

[0020] The milking robot 1 is adapted for automatic milking of animals,such as cows. Milk thus extracted by the milking robot 1 is transportedin the milk line 2 to the milk storage tank 3 by means of a pump (notillustrated) or similar. The milk is suitably filtered in the filterarrangement 4 while being transported in the milk line 2.

[0021] The filter arrangement 4, illustrated more in detail in FIGS. 2and 3, comprises a movable filter magazine including a central shaft 6,and two circular support plates 7. The magazine can be loaded with up tosix filter devices 8, each of which comprises a tube housing adisposable filter, such as a filter sock, and a support structure forsupporting the filter sock.

[0022] The support structure, illustrated in detail in FIG. 4, isadapted to support a filter sock (not shown), which suitably is threadover the support structure. The support structure comprises aring-shaped support 9 for engagement with the tube of the filter device8 and a coarse cylindrical mesh 10 or similar attached to thering-shaped support 9.

[0023] At the end of the coarse cylindrical mesh 10, which faces theincoming flow during filtration, is provided with a plate 11. Firstly,such plate provides a good support for the filter sock, and secondly itforces the milk or cleaning fluid to flow over the whole mesh, therebyobtaining an excellent filter capability.

[0024] A tubular member (not shown) may be arranged around the coarsemesh 10 at the other end thereof, i.e. adjacent to the ring-shapedsupport 9. Hereby, a dirt trap is formed by the volume delimited by thering-shaped support 9, the tubular member and the tube. Two smallopposite holes is provided in the tubular member adjacent thering-shaped support 9 such that a small flow out of the dirt trap isobtained.

[0025] Thus, dirt, which is filtered out and transported by the flow ofthe milk or cleaning fluid along the filter sock, is collected in thedirt trap and does stop up the filter.

[0026] The six filter devices 8 are positioned symmetrically around theshaft 6. The two plates 7 supports the six filter devices 8 in theirrespective ends. The shaft 6 is connected to the two plates 7, such thata revolving motion of the shaft 6 revolves the six filter devices 8.

[0027] Each of the six filter devices 8 is connectable in the milk line2 of the milking system, by moving the movable filter magazine.

[0028] An actuating device (not illustrated), such as an electric motor,is controlled by the controller to revolve the movable filter magazinestepwise.

[0029] A pneumatic or electric arrangement, also controllable by thecontroller 5, locks a filter device 8 in the milk line 2 by means of twopipe couplings 12 in a fluid-tight manner, such that a filter device 8connected to the milk line, can be used to filter milk transported inthe milk line 2 without any leakage.

[0030] When it is suitable to change filter in the milking system, e.g.due to the hygienic requirements, the filter device 8 connected to themilk line 2 is unlocked by the electric or pneumatic arrangement, and isremoved from the milk line 2 by revolving the movable filter magazine asperformed by the actuating device, and another filter device 8 from themovable filter magazine is positioned in the milk line 2, and locked tothe milk line 2 by the electric or pneumatic arrangement.

[0031] A sensor (not illustrated), such as an inductive sensor, may beused to detect the positions of the filter devices 8 in the movablefilter magazine, e.g. to ensure that a filter device to be connected inthe milk line 2 is in alignment therewith.

[0032] The sensor may be further used to detect the position of aparticularly marked filter device. That position may be used to indicatewhen all the filter socks in the movable filter magazine have been usedfor filtering, e.g. by positioning the movable filter magazine afterchange of filter socks in all filter devices 8 such that theparticularly marked filter device is detected when the movable filtermagazine has revolved a complete revolution.

[0033] The above-described embodiment, being provided with six filterdevices 8, generally requires a change of disposable filters only onceevery second day since the hygienic requirements prescribe change offilter socks three times per day and night. There is, however, aplurality of variations of the inventive filter arrangement, of whichsome are presented below.

[0034] If the milking system comprises a plate cooler (not illustrated)for pre-cooling of the milk, it is advisable to have a filter sock inthe milking line both during milking and during cleaning of the milkingsystem. It is usually adequate to use the same filter sock used duringmilking also during cleaning. If, however, an improved cleaning isdesired, an unused filter sock may be utilized in the filter deviceduring cleaning.

[0035] Furthermore, improved filtering may be achieved by changingfilter socks more often than required.

[0036] If the milking system does not comprise a plate cooler, it isadvisable to clean the milking system without any filter sock or supportstructure present in the filter device since a larger cleaning flow maythen be obtained.

[0037] A movable filter magazine provided with three filter devices istypically sufficient for change of the disposable filters only once perday and night in a milking system.

[0038] A movable filter magazine provided with three filter devices,each including a tube housing a filter sock and a support structure, andone filter device including an empty tube (i.e. a dummy filter device)is sufficient for filtering milk three times and cleaning three timeswithout a filter sock and a support structure present in the filterdevice. The controller 5 controls the connection/disconnection of thefilter devices 8 such that the filter device including the empty tube isconnected to the milking system while cleaning is performed, and thethree filter devices 8 provided with a respective filter sock arealternately connected to the milking system such that milk is filteredthrough a clean filter sock when three cleanings have been performed.Change of the disposable filters of the filter devices in the movablefilter magazine is then necessary.

[0039] Alternative, a magazine may be provided with three filter devices8, each including a tube housing a filter sock and a support structure,and three dummy filter devices 8, each including an empty tube,positioned alternately such that each filter device having a disposablefilter neighbors two dummy filter devices. Hereby, the actuating deviceonly needs to move the filter devices 8 a single step (i.e. a rotationof one sixth of a full revolution) to connect a filter device providedwith a clean filter sock for filtering of milk subsequent to thecleaning of the milking system where a dummy filter device is connectedin the milk line.

[0040] When it is time to change filter socks of the filter devices inthe movable filter magazine, e.g. as indicated by a signal generated bythe above-described sensor, or generated due to the period of timelapsed since the last change of filter socks having reached a thresholdvalue, the operator removes the filter socks of the disconnected filterdevices and provides the disconnected filter devices with clean filtersocks. The movable filter magazine is then manually rotated oneposition, such that a filter device 8 including a clean filter sock isconnected to the milk line 2. The filter sock of the last filter deviceis thereafter disposed of and replaced with a new clean one.

[0041] At the change of the filter socks, i.e. when the filter socks areremoved, the tubes and support structures may be cleaned.

[0042] Two lids (not illustrated) may be positioned to cover the ends ofthe filter devices 8 not connected to the milk line 2, to prevent dirtfrom entering the tubes and the filter socks.

[0043] Alternatively, a protecting housing (not illustrated) may beprovided for housing the whole filter arrangement 4, and thus dirt isprevented from entering the filter devices and contaminate the same.

[0044] A second embodiment of the present invention will now bedescribed with reference to FIGS. 5 and 6.

[0045] In this embodiment the movable filter magazine is a linearmagazine, i.e. the filter devices 8 are arranged along a line thereinand are supported by two support plates 13. An actuating device (notillustrated) is provided for linear movement of the movable filtermagazine, such that the filter devices 8 in the movable filter magazinecan be connected, one at a time, in the milk line 2 of the milkingsystem of FIG. 1, by means of two pipe couplings 12.

[0046] In other respects this embodiment does not differ from theprevious embodiment. Particularly, the discussion regarding the numberof filter devices and the number of filter devices for cleaning purposes(i.e. filter devices including an empty tube) to be used is equallyapplicable as regards this second embodiment.

[0047] The second embodiment of the present invention may easily befully automated by providing means (e.g. transport bands, robot arms,etc.) for removing used filter socks from the movable filter magazineand for arranging clean filter socks at empty positions of the movablefilter magazine.

[0048] It will be obvious that the present invention may be varied in aplurality of ways. All such variations as would be obvious for a personskilled in the art are intended to be included within the scope of thepresent invention.

1. An arrangement for filtering milk in a milking system, characterizedin that said arrangement comprises a movable filter magazine providedwith at least three filter devices (8), each of which comprises a tubehousing a disposable filter and a support structure for supporting thedisposable filter, and each of which is connectable in said milkingsystem for filtering milk therein; and an actuating device forconnecting each of said at least three filter devices, one at a time, insaid milking system for filtering milk therein, by moving said movablefilter magazine.
 2. The arrangement as claimed in claim 1 wherein saidmovable filter magazine is a revolver magazine, which is rotatablymovable.
 3. The arrangement as claimed in claim 1 wherein said movablefilter magazine is elongated, said at least three filter devices arearranged along a line in said movable filter magazine and said movablefilter magazine is linearly movable.
 4. The arrangement as claimed inany of claims 1-3 wherein said movable filter magazine is provided witha fourth filter device comprising an empty tube, and wherein said fourthfilter device is connectable in said milking system for cleaning of themilking system, and wherein said actuating device is adapted to connectsaid fourth filter device in said milking system while disconnecting oneof said at least three filter devices by moving said movable filtermagazine.
 5. The arrangement as claimed in claim 4 wherein said movablefilter magazine is provided with a fifth and a sixth filter device, eachof which comprises an empty tube, and each of which is connectable insaid milking system for cleaning of the milking system, and wherein saidactuating device is adapted to connect said fifth and sixth filterdevices, one at a time, in said milking system while disconnecting arespective one of said at least three filter devices by moving saidmovable filter magazine.
 6. The arrangement as claimed in any of claims1-3 wherein said movable filter magazine is provided with a fourth,fifth, and sixth filter device, each of which comprises a tube housing,a disposable filter and a support structure for supporting thedisposable filter, and each of which is connectable to said milkingsystem for filtering milk in the milking system, and wherein saidactuating device is adapted to connect said fourth, fifth and sixthfilter devices, one at a time, in said milking system for filtering milktherein while disconnecting a respective one of said at least threefilter devices by moving said movable filter magazine.
 7. Thearrangement as claimed in any of claims 1-6 wherein said disposablefilter is a filter sock.
 8. The arrangement as claimed in any of claims1-7 comprising a sensor for detecting a position of one of said filterdevices in said movable filter magazine.
 9. The arrangement as claimedin claim 8 wherein said sensor is further adapted for detecting theposition of a particularly marked filter device.
 10. A method forfiltering milk in a milking system, which milking system comprises amilking robot (1); a milk storage tank (3); a milk line (2) connectingsaid milking robot with said milk storage tank; and a controller (5) forcontrolling said milking system, said method being characterized by thesteps of: providing a movable filter arrangement (4) including a movablefilter magazine provided with at least three filter devices (8), each ofwhich comprises a tube housing, a disposable filter and a supportstructure for supporting the disposable filter, and each of which isconnectable, one at a time, to said milk line for filtering milktransported therein; moving one of said at least three filter devicesinto said milk line by means of an actuating device to connect said oneof said at least three filter devices to said milk line; filtering milkin said milking system by means of said one of said at least threefilter devices; moving said one of said at least three filter devicesfrom said milk line by means of said actuating device to disconnect saidone of said at least three filter devices from said milk line; andmoving another filter device of said at least three filter devices intosaid milk line by means of said actuating device to connect said anotherfilter device to said milk line.
 11. The method as claimed in claim 10wherein said movable filter magazine is provided with a fourth filterdevice including an empty tube for cleaning said milking system, andwherein said method further comprises the steps of: moving anyone ofsaid at least three filter devices from said milk line by means of saidactuating device to disconnect said anyone of said at least three filterdevices from said milk line; moving said fourth filter device into saidmilk line by means of said actuating device to connect said fourthfilter device to said milk line; cleaning the milking system with saidfourth filter device connected to said milk line; and moving said fourthfilter device from said milk line by means of said actuating device todisconnect said fourth filter device from said milk line.
 12. The methodas claimed in claim 10 wherein said movable filter magazine is providedwith a fourth, fifth and sixth filter device.
 13. The method as claimedin any of claims 10-12 wherein said method further comprises the stepsof: detecting a position of a particularly marked filter device by meansof a sensor provided in said filter arrangement; moving saidparticularly marked filter device from said position by means of saidactuating device; and alarming when said particularly marked filterdevice arrives at said position again.
 14. The method as claimed in anyof claims 10-13 wherein said steps of moving comprises a revolvingmotion of said movable filter magazine.